content: package com.example2;
  
  import android.app.Activity;
  import android.os.Bundle;
  import android.view.KeyEvent;
  
  import com.facebook.react.LifecycleState;
  import com.facebook.react.ReactInstanceManager;
  import com.facebook.react.ReactRootView;
  import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
  import com.facebook.react.shell.MainReactPackage;
  import com.facebook.soloader.SoLoader;
  
  public class MainActivity extends Activity implements DefaultHardwareBackBtnHandler {
  
      private ReactInstanceManager mReactInstanceManager;
      private ReactRootView mReactRootView;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          mReactRootView = new ReactRootView(this);
  
          mReactInstanceManager = ReactInstanceManager.builder()
                  .setApplication(getApplication())
                  .setBundleAssetName("index.android.bundle")
                  .setJSMainModuleName("index.android")
                  .addPackage(new MainReactPackage())
                  .setUseDeveloperSupport(BuildConfig.DEBUG)
                  .setInitialLifecycleState(LifecycleState.RESUMED)
                  .build();
  
          mReactRootView.startReactApplication(mReactInstanceManager, "Example2", null);
  
          setContentView(mReactRootView);
      }
  
      @Override
      public boolean onKeyUp(int keyCode, KeyEvent event) {
          if (keyCode == KeyEvent.KEYCODE_MENU && mReactInstanceManager != null) {
              mReactInstanceManager.showDevOptionsDialog();
              return true;
          }
          return super.onKeyUp(keyCode, event);
      }
  
      @Override
      public void invokeDefaultOnBackPressed() {
        super.onBackPressed();
      }
  
      @Override
      protected void onPause() {
          super.onPause();
  
          if (mReactInstanceManager != null) {
              mReactInstanceManager.onPause();
          }
      }
  
      @Override
      protected void onResume() {
          super.onResume();
  
          if (mReactInstanceManager != null) {
              mReactInstanceManager.onResume(this);
          }
      }
  }
  